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Biomedical subjects

Y Yano

Publications and source records attributed to Y Yano.

At least 379 records · Page 21Linked to original sources
PubMed1977

Cyclotron-produced Zn-62: its possible use in prostate and pancreas scanning as a Zn-62 amino acid chelate.

Zinc-62 is a positron emitter that localizes in pancreas, prostate, and liver. Cyclotron-produced Zn-62 was separated by column chromatography and evaluated in vivo as the chelate of five amino acids and also as 62ZnCl2. Tissue-distribution studies were done in normal animals from 0.7-23 hr after intravenous administration. Pancreas-to-liver ratios (per gram) of about 1.0 were found at 1.5 hr in studies on rats, dogs, and monkeys. Pancreas was as difficult to separate from liver in Zn-62 (amino acid) images as in [75Se] selenomethionine images. Some studies were done with Zn-65 to determine the effects of carrier zinc and molar ratios of ligand. The highest ratio of pancreas to liver in these studies was 1.44. This uptake ratio decreases with increasing amounts of histidine, but the ratio is increased by adding carrier zinc because there results a decrease in liver uptake and no change in the pancreas uptake. There is sufficient specificity of pancreas and prostate uptake to make feasible emission computed tomography with Zn-62.

Amino Acids↗
PubMed1977

Rubidium-82 generators for imaging studies.

Strontium-82, produced by spallation reaction with medium-energy proton beams, was used to evaluate Bio-Rex 70 and Chelex-100 ion-exchange resins for use in a compact Rb-82 generator. Adsorption of Sr-82 to the resin column, Rb-82 elution yields, Sr breakthrough, and 82Rb-Sr separation factors were determined for newly prepared columns and for longterm elution conditions. Separation factors of 10(7) to 10(8) were obtained with 2% NaCl elutions from Bio-Rex 70 resin columns while the separation factors was about 5 X 10(4) with the Chelex-100 resin column.

Evaluation Studies as Topic↗
PubMed1976

Dissociation between cytotoxic activity and delayed hypersensitivity against syngeneic or allogeneic tumor grafts.

Cytotoxicity against tumor-specific antigen and allogeneic antigens in mice was raised by immunization with viable tumor cells in saline, but not by immunization with tumor cells in complete or incomplete Freund's adjuvant. On the other hand, strong delayed hypersensitivity as demonstrated by macrophage migration inhibition was detected in the mice immunized with tumor cells in complete or incomplete Freund's adjuvant in both syngeneic and allogeneic systems. After immunization with viable tumor cells, delayed hypersensitivity was raised to a moderate degree in allogeneic, but not at all in syngeneic mice. Cytotoxicity was retained after a booster with syngeneic tumor cells in complete Freund's adjuvant in the mice which had been immunized with viable tumor cells. Cytotoxicity was raised after a booster with viable syngeneic tumor cells in the mice which had been immunized with tumor cells in complete or incomplete Freund's adjuvant. Thus, the development of cytotoxicity depended entirely on the presence of viable tumor cells as an immunogen. Activation of helper T cells was not found in the syngeneic mice immunized with viable tumor cells or tumor cells in complete or incomplete Freund's adjuvant. In allogeneic mice, the activity was facilitated slightly by immunization with viable tumor cells or tumor cells in complete Fruend's adjuvant but not with tumor cells in incomplete Freund's adjuvant. This sytem may be useful for analytical studies on cellular immunity, since cytotoxicity, delayed hypersensitivity, and helper cell activation can be induced in dissociated forms.

Animals↗
PubMed1975

Renaturation of yeast inorganic pyrophosphatase denatured in urea and guanidine hydrochloride.

The renaturation of yeast inorganic pyrophosphatase [EC 3.6.1.1] (PPiase) denatured in guanidine-HCl and urea was studied. The molecular weight of PPiase was estimated to be ca. 63,000-70,000 by means of Sephadex G-75 column chromatography in 8 M urea and 6 M guanidine-HCl and by electrophoresis on polyacrylamide gel containing 8 M urea. The activities of PPiase denatured in various concentrations of denaturants were measured in the presence and absence of the denaturants. In the presence of the denaturants, enzymatic activity decreased as the denaturant concentration increased up to 1.5 M guanidine-HCl and 4 7 urea. The activities of PPiase denatured in these denaturants were not restored by dilution with buffer. However, the enzymatic activities of PPiase denatured at concentrations higher than 1.5 M guanidine-HCl and 4 M urea were restored by dilution with Tris-HCl buffer (pH 7.5). The recovery of the enzymatic activities of PPiase denatured in 3 to 6 M guanidine-HCl and 6 to 8 M urea was to a level of about 90% of the native enzyme. Irreversible denaturation of PPiase in lower denaturant concentrations was prevented in the presence of sulfhydryl reagents, dithiothreitol, glutathione, and 2-mercaptoethanol. In irreversibly denatured PPiase, the amount of free SH groups decreased markedly. These results indicated that in lower denaturant concentrations, SH groups in PPiase are very oxidizable and their oxidation may cause irreversible denaturation. In higher denaturant concentrations where PPiase was denatured completely, the SH groups became less reactive. The conformations of renatured PPiases was investigated by means of N-bromosuccinimide oxidation, fluorescence emission spectra and circular dichroism spectra. The PPiase denatured in 6 M guanidine-HCl showed fully restored native conformation, as checked by these methods, although renatured PPiase gave a trough in the 280 nm region of slightly less magnitude than that of PPiase. On the other hand, PPiase denatured in 8 M urea showed restored enzymatic activity, but restoration of its conformation was incomplete as compared to PPiase denatured in 6 M guanidine-HCl. PPiase renatured from material denatured in lower denaturant concentrations, such as 4 M urea and 1.5 M guanidine-HCl, had quite a different conformation from the native enzyme as judged from CD spectra, N-bromosuccinimide oxidation and fluorescence spectra. Differences in PPiases denatured in urea and guanidine-HCl were discussed in connection with the possible modification of amino groups in PPiase by cyanate ions.

Bromosuccinimide↗
PubMed1975

Double-antibody radioimmunoassay for staphylococcal enterotoxin C2.

A sensitive double-antibody radioimmunoassay for staphylococcal enterotoxin C2 is described. The assay procedure employs anti-rabbit gamma globulin, prepared in goats, to precipitate the antigen-antibody complex of enterotoxin C2 and anti-enterotoxin C2. The test is sensitive to 100 pg of enterotoxin.

Animals↗